The present invention relates to a pusher and a puller, and a loader, an unloader, and a working apparatus having the pusher and the puller, which are suitable, for example, for handling circuit boards in operations in which semiconductor devices are installed on the circuit boards for manufacture of electronic circuit boards.
A number and types of components such as large and small connectors and electronic components that are mounted on an electronic circuit board have been increasing with diversification of functions of electronic equipment and increase in variety of electronic components. This involves advancement of techniques for microminiaturization and high-density mounting of electronic components and, on the other hand, involves use of large electronic circuit boards.
For example, a component mounting machine (b) for producing electronic circuit boards (a) as shown in FIG. 33 employs a loader (d) that pushes out circuit boards (c) from storage cassettes (f) to feed the boards to the component mounting machine (b) and an unloader (g) that pulls into storage cassettes (f) and stores electronic circuit boards (a) produced from circuit boards (c) mounted with electronic components (e) in the component mounting machine (b).
As shown in FIGS. 34 and 35, the loader (d) and the unloader (g) rectilinearly reciprocate a pushing member (j) or a pull piece (k) by an actuator, such as a screw shaft (h) and timing belt (i), that is reciprocated rectilinearly, and thereby load a circuit board (c) into the component mounting machine (b) or unload an electronic circuit board (a).
Both the storage cassettes (f) on the loader (d) from which the circuit boards (c) are pushed out and the storage cassettes (f) on the unloader (g) into which the electronic circuit boards (a) are pulled have a plurality of steps for receiving a circuit board (c) or an electronic circuit board (a) in each. The storage cassettes (f) are intermittently moved up and down by lifting and lowering mechanism not shown, so as to have the steps positioned sequentially at a specified height, in order that the circuit boards (c) may sequentially be pushed out from the steps or the electronic circuit boards (a) may sequentially be pulled into the steps.
As shown in FIG. 36, it is necessary for the pushing member (j) of the loader (d) to advance into a storage cassette (f) from a shelter position that is out of a lifting and lowering area (m) for the storage cassette (f), to push a circuit board (c) stored in the storage cassette (f), and to push out the board to an ulterior position that is out of the lifting and lowering area (m) for the storage cassette (f). As shown in FIG. 37, it is necessary for the pull piece (k) of the unloader (g) to pull an electronic circuit board (a) in a shelter position that is out of a lifting and lowering area (m) for a storage cassette (f), into the storage cassette (f) that is in the lifting and lowering area (m).
For this purpose, as shown in FIGS. 34 to 37, the loader (d) and the unloader (g) partially project far from lifting and lowering areas (m) for the storage cassettes (f) by a size (t) that is a sum of a size (S) in a direction in which a circuit board (c) or an electronic circuit board (a) is pushed or pulled and of an auxiliary space including a safety space for interference prevention and a supporting space for the pushing member (j) or the pull piece (k).
Movable parts that project partially and greatly in this manner are prone to encumber workers and surroundings and to make trouble. With such a great projection, a size of the loader (d) or the unloader (g) in a direction in which a circuit board (c) or an electronic circuit board (a) is moved is as large as on the order of 2.5 times that of the circuit board (c) or the electronic circuit board (a) that are to be handled, and therefore the sizes of the loader (d) and the unloader (g) for boards having a size of 200 mm are as large as on the order of 500 mm. A space to be occupied for installation of such a loader or such an unloader in combination with the component mounting machine (b) has to be so large that nowaday demand for space saving cannot be satisfied.
Where the component mounting machine (b) handles and mounts flip chip semiconductor devices, particularly, simplification of a geometry of junction between semiconductor devices and a circuit board, simplification of operations, and reduction in distance for the junction can be achieved by such a mounting method that bumps provided on electrodes on a semiconductor wafer are directly joined to electrodes on a circuit board (c), or the like. Such mounting operations, however, have to be performed in a clean room, and a monthly running cost required for light and fuel in a clean room having an area of 600 m2, for example, is supposed to reach thirty million yen. In this case, therefore, such great projections on the loader (d) and the unloader (g) as described above are particularly problematic.
An object of the present invention is to provide a pusher and a puller which allow quantities of projection of a pushing mechanism and a pulling mechanism in directions of push and pull to be smaller than quantities of push and pull and which are suitable for space saving, and to provide a loader, an unloader, and a working apparatus having the pusher and the puller.
A first aspect of the invention provides a pusher for pushing an object from a first position to a second position, the pusher comprising: a leaf spring, a driving section for nipping the leaf spring to advance and retract it in a longitudinal direction so that advancement of a fore end portion of the leaf spring in a pushing direction causes the object facing the fore end portion of the leaf spring to be pushed from the first position to the second position, a direction changing section for bending a side of a tail end portion of the leaf spring being advanced and retracted relative to a side of the fore end portion extending in the pushing direction so as to change directions of advancement and retraction of the leaf spring at the direction changing section, and guides for guiding the side of the fore end portion and the side of the tail end portion of the leaf spring with respect to the direction changing section in the directions of advancement and retraction.
In such a configuration, the leaf spring exhibits a high flexural rigidity and an excellent rectilinearity because of its thickness, thickness distribution along a direction of a width thereof, shape of curve or bend with respect to the direction of the width, and the like, drive for advancement and retraction by the driving section is efficiently transmitted to the fore end portion directly or through the guides, the direction changing section, and the like, the facing object is pushed away without escape even though the fore end portion is in a released status in which the fore end portion protrudes from a guide on the side of the fore end portion when being advanced, and consequently, the leaf spring is capable of reliably pushing by a specified quantity the object to be pushed that is ahead of an initial push position on condition that the leaf spring is guided to immediate front of the initial push position. Besides, the direction changing section in middle of the leaf spring changes the direction of advancement and retraction of the spring from the pushing direction by bending the side of the tail end portion relative to the side of the fore end portion, and therefore a partial projection of the side of the tail end portion of the leaf spring, the guide for that side, and the like that is backward with respect to the pushing direction can be avoided, so that the problems with the partial projection are resolved. Moreover, a length from the direction changing section to the immediate front of the initial push position has only to be set in a range that narrowly satisfies a guiding function the guide on the side of the fore end portion performs by itself or in cooperation with the direction changing section for straight advancement of the fore end portion of the leaf spring, and a size of a site for installation of the pusher can be sufficiently smaller than a quantity of push by the fore end portion on the object to be pushed, regardless of the quantity, for space saving. As for a direction in which the side of the tail end portion of the leaf spring is bent for the change of the directions of advancement and retraction, selection of a side having the more room of an installation area prevents occurrence of problems such as obstruction to other equipment and expansion of the installation area on a side opposite to the direction of the bend.
Provided that a pair of rollers in the driving section, that is, both a driving roller and a pressure roller in pressure contact with the driving roller are shaped cylindrically, and that the driving roller also performs as a guide roller for changing the directions of advancement and retraction of the leaf spring, the change of the directions of advancement and retraction of the leaf spring and the drive for the advancement and retraction can be achieved by one and the same means in one place without strain resulting from slide friction, and simplification of structure and space saving are furthered.
In this case, provided that a position in which the pressure roller is in pressure contact with the driving roller is generally on a bisector passing through a center of the driving roller between the side of the fore end portion and the side of the tail end portion of the leaf spring, the pressure roller acts on a flattest portion of the leaf spring extending along the driving roller because the leaf spring having a curve with respect to the direction of the width is bent for the change of the directions of advancement and retraction while being flattened along the cylindrical shape of the driving roller. Accordingly, this arrangement prevents a great stress in the leaf spring that may be caused by forcible flatting of a portion of the leaf spring resistant to flatting, with pressure between the driving roller and the pressure roller acting out of the above-mentioned position, and thereby extends a life span of the leaf spring.
With the driving roller and the pressure roller configured so as not to come into contact with side edges of the leaf spring, a nipping pressure between the driving roller and the pressure roller is prevented from reaching both the side edges of the spring curved with respect to the direction of the width or both the side edges provided with bent portions, thick portions or the like. Thus mechanical external forces are prevented from acting on the side edges at which a quantity of deformation involved by the change of the directions of the leaf spring and termination of the change is large owing to the shape of the leaf spring and which thereby suffer damages easily, and the life span of the leaf spring is thereby further extended.
Provided that the guide on the side of the fore end portion and the guide on the side of the tail end portion have at least one pair of non-cylindrical rollers that is a combination of a concave roller and a convex roller or the like fitting with the shape of the leaf spring having a curve with respect to the direction of the width, the leaf spring can stably be advanced and retracted by the guides in cooperation with the direction changing section, without stress by the guides, with help of a high rectilinear rigidity of the leaf spring while the shape of the leaf spring having the curve with respect to the direction of the width is held.
Provided that a surface in which the directions of the leaf spring are changed is a horizontal surface perpendicular to a direction of gravity, the direction of the width of the leaf spring in which the leaf spring resists deformation points in the direction of gravity, so that droop by gravity of the fore end portion protruded from the guide can be prevented for ensuring stable push on an object to be pushed.
With a hardness of the leaf spring on the order of 430 to 489 Hv (Vickers hardness), the life span of the leaf spring is extended because stress by the change of the directions of advancement and retraction is reduced without impairment of characteristics on pushing.
With a roughness expressed by a standard numerical sequence of maximum heights on the side edges of the leaf spring not more than 25 S, the life span of the spring is extended because there is little unevenness having such a size that cracks and fracture may be caused by great deformation such as the bend for the change of the directions of advancement and retraction.
With a radius of curvature of the leaf spring with respect to the direction of the width on the order of 30 to 50 mm, satisfactory rectilinearity is achieved, a quantity of deformation by the change of the directions of the advancement and retraction is made smaller, stress is thereby reduced, and the life span of the spring is extended.
Provided that the leaf spring is cut from a material with a longitudinal direction of the spring set perpendicular to a drawing direction for the material, linear pattern of indentation caused by rollers in the direction perpendicular to the drawing direction in drawing of the spring material remains on the leaf spring in the longitudinal direction of the spring, directions of bending and stretching in the change of the directions of advancement and retraction of the leaf spring intersect the linear pattern by the rollers, stress concentration and mechanical stress that are caused by the deformation are reduced, and therefore damage to the leaf spring at an early stage can be prevented.
A second aspect of the invention provides a puller for pulling an object from a first position to a second position, the puller comprising: a leaf spring with a hook section on a fore end portion thereof, a driving section for nipping the leaf spring to advance and retract it in a longitudinal direction so that retraction of a fore end portion of the leaf spring in a pulling direction causes the object to be hooked by the hook section and pulled from the first position to the second position, at least one direction changing section for bending a side of a tail end portion of the leaf spring being advanced and retracted relative to a side of the fore end portion extending in the pulling direction so as to change direction of advancement and retraction of the leaf spring at the direction changing section, and guides for guiding the side of the fore end portion and the side of the tail end portion of the leaf spring with respect to the direction changing section in the directions of advancement and retraction.
In such a configuration, the leaf spring exhibits a high flexural rigidity because of its thickness, thickness distribution along a direction of a width thereof, shape of curve or bend with respect to the direction of the width, and the like, and drive for advancement and retraction by the driving section is satisfactorily transmitted to the fore end portion. In particular, an extensional rigidity of the leaf spring is so high that pull for retraction drive by the driving section is efficiently transmitted to the fore end portion directly or through the guides, the direction changing section, and the like, and an object to be pulled in an initial pull position can be pulled reliably without play and loss. Moreover, a distance from a terminal position of the pull to the direction changing section can be set smaller than a quantity of pull from the initial pull position to the terminal pull position, irrespective of the quantity of pull from the initial pull position to the terminal pull position, on a necessary minimum condition that the direction changing section can be provided. Even if a guide on the side of the fore end portion is provided so as to extend to the initial pull position, a maximum quantity of advancement of the leaf spring can be restricted so as to be roughly as small as the quantity of pull because the fore end portion of the leaf spring has only to hook an object to be pulled, in a range from the initial pull position to the terminal pull position. As a result, a size of projection of the puller can be minimized according to the quantity of pull, for space saving. As a direction in which the side of the tail end portion of the leaf spring is bent, selection of a side having the more room of an installation area prevents occurrence of problems such as obstruction to other equipment and expansion of the installation area on a side opposite to the direction of the bend.
Provided that the guide does not reach an advanced position of the fore end portion of the leaf spring, and that the side of the fore end portion that protrudes from the guide with advancement of the leaf spring has a curved portion that is curved with respect to the direction of the width and that extends over a length range longer than the protruded portion, the side of the fore end portion of the leaf spring protruded from the guide can be hooked reliably on an object to be pulled, without escape and can be pulled without aid of the guide because the side of the fore end portion ranging from a portion that is guided by the guide to an end of the protrusion is the curved portion curved with respect to the direction of the width and having a high flexural rigidity and an excellent rectilinearity. Accordingly, a quantity of fixed projection of the guide can be made smaller than the quantity of pull by a distance between the guide and the advanced position of the leaf spring.
With the direction changing section provided as guide rollers, rotation of the guide rollers with movement of the leaf spring prevents slide friction between the leaf spring and the direction changing section and the drive for advancement and retraction of the leaf spring with the change of directions is performed without strain.
With the side of the tail end portion of the leaf spring connected to a winding section, a space required for handling of a length of the leaf spring can be reduced by a size of a portion of the leaf spring that may be wound into the winding section.
With the direction changing section also performing as the winding section, maximal simplification of structure, further miniaturization and cost reduction are achieved.
Provided that a surface in which the directions of the leaf spring are changed is a vertical surface, required component members can be arranged with use of a dead space in the vertical surface, for saving horizontal space.
With provision of two direction changing sections, a space for arrangement of required component members can easily be made still smaller.
Provided that a hardness of the leaf spring is on the order of 370 to 429 Hv, suppression of stress and prolongation of life span of the spring are achieved even though there are two direction changing sections and/or even though the spring may be wound by the winding section.
A roughness of the side edges of the leaf spring equal to or less than 25 S is preferable by the same reason as in the pusher.
A radius of curvature with respect to the direction of the width of the leaf spring on the order of 20 to 50 mm provides a rectilinear rigidity required for pull without use of the guide, without reducing durability. As the radius approaches about 20 mm, a length of a portion that can be omitted of the guide forms an increasing proportion of a full length of the guide and a space for fixation and installation of the puller can be made small to that extent.
The leaf spring cut from a material with a longitudinal direction of the spring set perpendicular to a drawing direction for the material is preferable by the same reason as in the pusher.
A third aspect of the invention provides a loader for feeding a handling section with board-like members stored in a plurality of steps of a storage cassette, the loader comprising: a lifting and lowering section for lifting and lowering the storage cassette, and a pushing section for pushing the board-like member from the step of the storage cassette to the handling section, wherein the pushing section comprises: a leaf spring, a driving section for nipping the leaf spring to advance and retract it in a longitudinal direction so that advancement of a fore end portion of the leaf spring into the storage cassette in a pushing direction causes the board-like member facing the fore end portion of the leaf spring to be pushed from the storage cassette to the handling section, a direction changing section for bending a side of a tail end portion of the leaf spring being advanced and retracted relative to a side of the fore end portion extending in the pushing direction so as to change directions of advancement and retraction of the leaf spring at the direction changing section, a position detecting section for detecting a position of the leaf spring, and an abnormality detecting section for detecting an abnormal action of the leaf spring on the basis of a position detection signal from the position detecting section.
In such a configuration, the lifting and lowering section lifts and lowers the storage cassettes loaded thereon so that the board-like members stored in the steps may sequentially be positioned at a specified height subjected to pushing by the pushing section. In the pushing section, a high rectilinear rigidity of the leaf spring owing to its thickness, thickness distribution along the direction of the width, shape of curve or bend with respect to the direction of the width, and the like ensures efficient transmission of drive for advancement and retraction by the driving section to the fore end portion directly or through the guides, the direction changing section, and the like, advancement of the fore end portion into a storage cassette without aid of a guide, and reliable push of the facing board-like member without escape and service of the member for handling in other sections under a condition that the guides are provided so as to extend to immediate front of a lifting and lowering area for the storage cassettes. Besides, the direction changing section in middle of the leaf spring changes the direction of advancement and retraction of the spring from the pushing direction by bending the side of the tail end portion relative to the side of the fore end portion, and therefore problems with a great partial projection of the side of the tail end portion of the leaf spring, the guide for that side, and the like from the lifting and lowering section can be prevented. Moreover, a length from the direction changing section to the immediate front of the lifting and lowering area has only to satisfy a guiding range that the guide on the side of the fore end portion requires for rectilinearly advancing the fore end portion of the leaf spring by itself or in cooperation with the direction changing section, and a size of a site for installation of the pushing section can be sufficiently smaller than a quantity of push by the fore end portion on the board-like member, regardless of the quantity, for space saving. As for a direction in which the side of the tail end portion of the leaf spring is bent for the change of the directions of advancement and retraction, selection of a side having the more room of an installation area prevents occurrence of problems such as obstruction to other equipment and expansion of the installation area on a side opposite to the direction of the bend.
Also in the loader, preferably, a pair of rollers in the driving section, that is, both a driving roller and a pressure roller in pressure contact with the driving roller are shaped cylindrically, the driving roller doubles as a guide roller for changing the directions of advancement and retraction of the leaf spring, the guide on the side of the fore end portion and the guide on the side of the tail end portion have at least one pair of non-cylindrical rollers that is a combination of a concave roller and a convex roller or the like fitting with the shape of the leaf spring having a curve with respect to the direction of the width, and the pairs of non-cylindrical rollers on the side of the fore end portion are provided in immediate front of the lifting and lowering area that is immediate front of a protruded position of the leaf spring in the pushing section.
Provided that a surface in which the directions of the leaf spring are changed is a horizontal surface, a dead space extending in a direction at right angles to a loading direction in the lifting and lowering section can be used effectively.
A fourth aspect of the invention provides an unloader for taking board-like members out of a handling section into a plurality of steps in a storage cassette, the unloader comprising: a lifting and lowering section for lifting and lowering the storage cassette, and a pulling section for pulling the board-like member from the handling section into the step in the storage cassettes, wherein the pulling section comprises: a leaf spring with a hook section on a fore end portion thereof, a drive section for nipping the leaf spring to advance and retract it in a longitudinal direction so that retraction of the fore end portion of the leaf spring in a pulling direction causes the board-like member to be hooked by the hook section and pulled from the handling portion to the step of the storage cassette, at least one direction changing section for bending a side of a tail end portion of the leaf spring being advanced and retracted relative to a side of the fore end portion extending in the pulling direction so as to change directions of advancement and retraction of the leaf spring at the direction changing section, and guides for guiding the side of the fore end portion and the side of the tail end portion of the leaf spring with respect to the direction changing section in the directions of advancement and retraction.
In such a configuration, the lifting and lowering section lifts and lowers the storage cassettes loaded thereon so that the steps may sequentially be positioned at a specified height subjected to pull of a board-like member by the pulling section. In the pulling section, a flexural rigidity of the leaf spring owing to its thickness, thickness distribution along the direction of the width, shape of curve or bend with respect to the direction of the width, and the like ensures satisfactory transmission of drive for advancement and retraction by the driving section to the fore end portion. In particular, because of a particularly high extensional rigidity of the leaf spring, pull of retraction drive by the driving section is efficiently transmitted to the fore end portion directly or through the guides, the direction changing section, so that a board-like member in an initial pull position can be pulled reliably without play and loss and can be stored into a storage cassette. Moreover, a distance from a terminal pull position where the pull terminates to the direction changing section can be set smaller than a quantity of pull from the initial pull position to the terminal pull position, irrespective of the quantity of pull from the initial pull position to the terminal pull position, on a necessary minimum condition that the direction changing section can be provided. Even if a guide on the side of the fore end portion is provided so as to extend to the initial pull position, the distance can be restricted so as to be roughly as small as the quantity of pull because the fore end portion of the leaf spring has only to hook a board-like member in a range from the initial pull position to the terminal pull position. As a result, a size of a site for installation of the pulling section can be made sufficiently small according to the quantity of pull, for space saving. As a direction in which the side of the tail end portion of the leaf spring is bent, selection of a side having the more room of an installation area prevents occurrence of problems such as obstruction to other equipment and expansion of the installation area on a side opposite to the direction of the bend.
Also in the unloader, preferably, a part of the side of the fore end portion of the leaf spring is formed as a curved portion curved with respect to the direction of the width and extending over a length range longer than a range that is protruded from the guide with advancement of the leaf spring, the direction changing sections are guide rollers, the tail end portion of the leaf spring is connected to a winding mechanism, a surface in which the directions of the leaf spring are changed is a vertical surface, and two direction changing sections are provided.
A fifth aspect of the invention provides a working apparatus for performing repetitive operations on a plurality of board-like members, the apparatus having a mounting machine that repeats delivery of a board-like member from a take-in section, operations on the delivered board-like member, and delivery of the finished board-like member to the take-out section, the loader of the third aspect of the invention for feeding a board-like member stored in a plurality of steps in a first storage cassette, to the take-in section of the mounting machine, and the unloader of the fourth aspect of the invention for taking out a board-like member from a carry-out section of the mounting machine and storing the member into a plurality of steps in a second storage cassette.
With use of the loader and the unloader having the above characteristics in such a configuration, handling by the mounting machine a board-like member stored in a plurality of steps in a storage cassette, performing specified operations on the board-like member, and storing the finished board-like member into a plurality of steps in a storage cassette can be repeated automatically, while saving space for the whole apparatus including the loader and the unloader is achieved.
Provided that both the pusher and the puller in the above configuration have a rectilinear-advancement guide for preventing flexure of the leaf spring, as a guide on the side of the tail end portion of the leaf spring, flexure of the leaf spring being advanced and retracted can be prevented for facilitating smooth operation while cost reduction is achieved by employment of common components.
With provision of an abnormal collision detecting section for detecting abnormal collision in which the fore end portion of the leaf spring encounters a load not smaller than a given magnitude, such abnormal collision can be coped with. In this case, such abnormality can automatically be coped with if a controlling section is provided which stops drive of the leaf spring in response to abnormal collision detection signal from the abnormal collision detecting section. The abnormal collision detecting section may have a controlling system that is provided in a drive system for the leaf spring and that cuts off transmission of the drive when the abnormal collision detecting section detects abnormality.
With provision of a position detecting section for the leaf spring and an abnormality detecting section that detects malfunction of the leaf spring on basis of position detection signal for the leaf spring from the position detecting section, such malfunction can be coped with. In this case, the abnormality detecting section may detect malfunction of the leaf spring on basis of position detection signal and an operating condition of the pusher at the moment or may detect malfunction of the leaf spring on basis of comparison between position detection signals for two or more positions from detecting sections.
The malfunction can be managed, with provision of a travel quantity detecting section for detecting a quantity of travel of the leaf spring and an abnormality detecting section for detecting abnormality of the leaf spring on basis of travel quantity detection signal from the travel quantity detecting section. In this case, the abnormality detecting section may detect abnormality of the leaf spring by comparison of the quantity of travel of the leaf spring detected by the travel quantity detecting section with a reference quantity of travel that is a quantity of travel of a normal leaf spring.
The travel quantity detecting section may have sections to be detected that are provided along a longitudinal direction on the side of the fore end portion of the leaf spring, a detecting section for detecting the sections to be detected, at a specified position adjacent to a course of advancement and retraction of the leaf spring, and a counter for counting a number of times the detecting section has detected the sections to be detected with advancement and retraction of the leaf spring, and the counted number may be regarded as a quantity of travel of the leaf spring.
The abnormality detecting section may detect abnormality of the leaf spring on basis of travel quantity detection signal for the leaf spring and an operating condition of the pusher at the moment or may detect abnormality of the leaf spring by comparison between quantities of travel of two or more sites on the leaf spring.
The abnormality detecting section may monitor pulse signal generated from the detecting section that is detecting the sections to be detected on the leaf spring, and a pulse width of the pulse signal exceeding a specified quantity may be judged as abnormality of a motor for driving the leaf spring.
With provision of a torque detecting section for detecting a value of torque of the motor for driving the leaf spring, the abnormality detecting section may compare the value of torque with a quantity of travel of the leaf spring and may detect occurrence of slip between the leaf spring and the driving section for the leaf spring, so that malfunction can be coped with.
The reference quantity of travel of the leaf spring may be set in conformity with a push stroke for a board-like member that requires the largest push stroke for various types of board-like members or reference quantities of travel of the leaf spring may previously be set according to types of board-like members and may be switched with recognition of an identification code provided on a board-like member.